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In this Article

• What is Fragile X syndrome?
• What causes Fragile X syndrome?
• What keeps the FMR1 gene from producing FMRP in Fragile X syndrome?
• Patient Discussions: Fragile X Syndrome - Describe Your Experience
• Fragile X Syndrome Glossary
• Fragile X Syndrome Index

What is being done to develop treatments or a cure for Fragile X syndrome?

Since the late 1960s, the NICHD has supported the research of scientists who are trying to understand Fragile X. The work of these scientists continues to increase knowledge about this disorder, but many questions still remain unanswered.

In 1991, researchers funded by the NICHD identified FMR1 as the gene that, when mutated, causes Fragile X. Since that time, the NICHD has been a major source of funds for Fragile X research. In addition, a number of private, non-profit organizations, including the FRAXA Research Foundation, the National Fragile X Foundation, and the Conquer Fragile X Foundation, are also dedicated to continuing Fragile X research and to raising awareness of the disorder.

In the Children's Health Act of 2000, congress authorized the NICHD to create and maintain at least three research centers specifically for Fragile X research. In March 2003, the NICHD announced awards for the following Mental Retardation and Developmental Disabilities Research Centers to house the new Fragile X Research Centers: the University of North Carolina, in affiliation with the University of Kansas; the University of Washington; and Baylor College of Medicine. The efforts of these new centers began in late spring 2003.

Also in 2000, the NICHD initiated, with financial collaboration from the FRAXA Research Foundation and the National Institute of Mental Health, a special research program to support noted scientists around the world in an effort to find treatments and a cure for Fragile X.

Some of these researchers are examining Fragile X at the molecular level. Some of the questions they are asking include:

• Why does the FMR1 gene have an increased number of CGG repeats in the promoter region?
• What causes the increased methylation of the promoter region, which blocks the gene from producing FMRP?
• What is the role of FMRP in the brain?
• How does FMRP help other proteins, and what are the functions of those proteins?

The findings from such research may help to prevent or reverse mental retardation and other symptoms of Fragile X.

To advance the field of Fragile X research, scientists are also working to create models of how the human brain works. Some are creating computer programs that imitate the way the human brain learns and remembers. Other scientists modify genes in other animals, such as mice and fruit flies, to try new interventions or treatments. For instance, researchers can replace the FMR1 gene in a normal mouse with a mutated human FMR1 gene. Such "transgenic" animals are key to much of the current research. For example, one recent study is examining the effects of a certain substance in transgenic mice that don't produce FMRP. Researchers believe that this compound could help regulate brain processes that are impacted by a lack of FMRP. Using these mice, researchers can test this new intervention to ensure that it is safe and effective before the intervention is used with humans.

Can we prevent or cure Fragile X? Two decades ago, researchers might have said "No." Now scientists are exploring several promising possibilities, including:

• Gene repair, gene reactivation, and gene therapy. Scientists may be able to induce certain brain chemicals to repair defective FMR1 genes. Researchers also seek ways to prevent or reverse methylation, the process that interferes with the instructions for making FMRP and inactivates the FMR1 gene. Still other scientists are trying to determine if it is possible to replace defective genes with stable, working copies of the FMR1 gene. This type of gene research involves a number of challenges. First, it is important that researchers learn how many cells are needed to produce the right amount of protein. Too much of the protein may be as harmful as too little, so finding the right balance is crucial. Another difficulty lies in targeting only the defective FMR1 genes for repair or reactivation, without affecting other healthy genes. Further, replacing genes, especially those involved in brain function, carries additional problems and risks. However, researchers continue to pursue these avenues. NICHD-supported and other sponsored research is already underway to study the possibility of reversing methylation on the FMR1 promoter sequence, prenatally. Success in this area may allow scientists to "reactivate" FMRP production before a child is born. Other gene research is also underway
• Protein replacement. Scientists already make FMRP in the lab. At present, however, they are unable to get FMRP to the brain, partly because the FMRP molecule is too large to pass through the structures that protect the brain. Someday people with Fragile X may be able to take a pill or injection of FMRP to relieve many of the symptoms of Fragile X.
• Protein substitute through medication. Scientists may be able to use other substances to take the place of FMRP in certain brain processes. Using these substitutes, brain processes and other functions of FMRP may be able to occur normally. For example, new drugs may be able to regulate processes in the brain, like communication between neurons, that seem to be affected by low levels of FMRP.

While these research avenues are promising, none of them has progressed enough to provide immediate help to someone with Fragile X. Parents, families, and caregivers should work together with health care professionals, educators, and therapists to ensure that those affected by Fragile X receive the care that they need.

This is an exciting time in Fragile X research. Dr. James Watson, who received the Nobel Prize in Physiology or Medicine for the co-discovery of the double-helix structure of DNA, believes that science will be able to defeat the negative effects of Fragile X. He predicts, "Our wealth of research strategies and technologies may soon lead to new forms of therapy and medication. Someday we may be able to prevent the mental retardation and other symptoms of Fragile X."